Natto is Japan's infamous, divisive, so-called 'superfood' made by fermenting soybeans (Glycine max) with the bacterium Bacillus subtilis. The story of natto finds itself stretched everywhere: from the migrations of the last Ice Age to the frontiers of biotechnology, from the streets of Edo to the supermarket refrigerator, from the invention of the petri dish to the modern clinical trial; and everywhere in-between.This is the first comprehensive English-language book that explores all aspects of natto: its history, science, and technology, with the hope more people will come to appreciate its curious qualities.